The invention relates to a pressure limiting valve, in particular for common rail systems.
Pressure-limiting valves for common rail systems are used to limit the pressure in a high-pressure reservoir or a common rail injection device. The pressure-limiting valve performs the task of limiting the maximum rail pressure in the system in order to protect the system components in the event of a malfunction. The pressure-limiting valve has further the task of providing a minimum pressure in the high-pressure reservoir (common rail) for an emergency operation of a motor vehicle; thus enabling the motor vehicle to reach the repair shop under its own propulsion.
Such a pressure-limiting valve is known from the WIPO patent application WO 2004/083695 A1. This pressure-limiting valve has a valve support and a valve insert which is connected to the valve support, a valve piston being mounted such that it can slide in the valve insert. The valve piston acts with a valve seat face on a valve seat on the valve insert, the valve seat face being seated on the valve seat in the closed state of the pressure-limiting valve. The closing force of the valve piston is produced by a compression spring which is accommodated in the valve support. The pressure-limiting valve is inserted into a housing which comprises a high-pressure connection to a high-pressure reservoir (common rail) and a low-pressure connection for a return line. In so doing, the valve piston in the valve insert separates a high-pressure valve chamber, into which the high-pressure connection opens out, from a low-pressure chamber, the low-pressure connection leading out of said low-pressure chamber.